A modified form of cellulose found in the exoskeletons of insects and crustaceans
Non-polarity and insolubility characterize biological compounds
Alpha helix and beta pleated sheets are examples of the secondary level of
Components of nucleic acids
Include a five-carbon sugar, a phosphate group, an organic nitrogen containing base, and
Fructose and galactose
all have the same six carbon atoms, twelve hydrogen atoms, and six oxygen atoms, just as
glucose, but they are named differently because they are alternate forms of the
monosaccharide, glucose .
are created with phosphodiester bonds.
Nitrogen and carbon
are common to all organic molecules.
is nonpolar and high in energy because they are largely composed of hydrocarbons.
Lipids serve as important energy stores and is a major component of plasma membranes.
The functional group -COOH
has acidic properties and would release hydrogen ions in an aqueous (water) solution.
The peptidoglycan of the bacterial cell wall
contains a carbohydrate matrix linked together by short chains of amino acids.
apparently permit the passage of only proteins inward and outward, but RNA only outward.
Mitochondria and chloroplasts
are the other organelles besides the nucleus that contain DNA.
The Golgi apparatus and ER
are organelles that participate in the synthesis and modification of enzymes targeted to the
The principles of cell theory or cell doctrine include the following:
All living organisms are composed of one or more cells, cells are the smallest unit of living
organisms, and new cells form from pre-existing cells by cell division.
The most accurate endomembrane route through which a protein is secreted from a cell
is rough endoplasmic reticulum> Golgi apparatus> vesicles> plasma membrane.
A match of structures and functions
Cytoskeleton-microfilaments, nucleus- DNA replication, cell membrane-lipid bilayer, and Golgi
apparatus-modification, processing, and sorting of macromolecules. Endoplasmic reticulum
is responsible for the biosynthesis of proteins that are destined for secretion by the cell.
Tissues such as the gonads that produce steroids
are likely to be rich in smooth endoplasmic reticulum.
A description of ribosome biosynthesis and structure could include the following information:
Ribosomes are composed of two subunits of RNA and proteins and ribosomal proteins are
produced in the cytosol.
is the diffusion of water across a membrane in response to the concentration of one or more of
are not very soluble in water, because they possess long stretches of non- polar amino acids
that are hydrophobic.
The cell's transactions with the environment mediated by its plasma membrane include:
ingesting food as molecules and sometimes as entire cells, returning waste and other molecules
back to the environment, responding to a host of chemical cues, and passing of messages to
Carbohydrate chains on the outer surface of the plasma membrane:
are often marker molecules that identify the cell-type.
The part of a membrane protein that extends through the phospholipid bilayer
is primarily composed of amino acids that are non-polar. Functions of a typical plasma membrane include:
transport of water and bulk material, selective transport of certain molecules and material,
reception of information, and expression of cellular identity.
In bacteria, fungi, and plants
the high internal pressure generated by osmosis is counteracted by the mechanical strength of
their cell walls.
The actual transport of protons by the proton pump is mediated
by a transmembrane protein which undergoes a change in its conformation.
cannot carry out endocytosis.
For the process of diffusion to occur
molecules must move from areas of high concentration to areas of lesser concentration until
equilibrium is reached.
Communication among cells is
a hallmark of multicellular organisms.
Tight and anchoring junctions cause
cells to adhere tightly to each other.
Specific protein receptors are present for
signal amplification, signal transduction, intracellular receptors, binding to DNA, and signaling
to other cells. Paracrine signals
Signals with short-lived, local effects
Synaptic signaling requires
neurotransmitters to be released into the synaptic gap.
In the digestive tract
tight junctions develop connections to form a sheet that prevents leakage of small molecules.
Small molecules or ions can pass from one cell to another
A cell biologist has blocked
the chemically-gated ion channels in a lab rat's liver tissue by using a chemical that prohibits
binding of a signal molecule.
commonly used to regulate signal transduction pathways because the addition or removal of a
phosphate group can expose or hide potential binding sites in proteins.
Certain key molecules can regulate biochemical pathways by controlling the rates of enzymatic
reactions by binding at
A molecule that closely resembles the shape of a substrate for an enzyme Oxidation
gain of e-
loss in electrons.
Reactions that occur spontaneously and release free energy
have specific substrates with which they interact.
The inorganic non-protein components that participate in enzyme catalysis
The unit of heat & unit of chemical energy
appear not to produce functional products.
has more genes than humans.
is likely to produce pseudogenes Today, gene swapping between two species
infrequent but possible; it happened more often in the distant past.
Genes controlling basic m